UTF-8Chemical Reactions: Rates227223152
Reaction Rates, Catalysis, and Energy: Factors affecting reaction rates.
During chemical reactions, chemical energy can be released by converting it into heat, raising the temperature. Also, the reverse may happen, heat energy can be converted into chemical energy, lowering the temperature.*
Challenge: You are a research chemist who wants to produce more of a particular chemical and you need atoms to react with each other more quickly. How might you make the reactions go faster? To achieve your goal, try the following:
1. Evenly distribute atoms by clicking the add atom button , and then clicking inside the container to place an atom at that location. (more atoms = more concentrated).
2. Set the temperature slider.
3. Run the model .
4. Watch the model and the graph to determine how long it take for about 80% of your atoms to stay bonded.
5. Reset the model, and repeat the above steps, but vary the concentration and/or the temperature.
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*A Note about the model: Because we want to see how the temperature at which a reaction occurs can affect the reaction rate, we need to hold the temperature constant during the reaction. However, the reaction itself can cause a change in temperature. To eliminate the changes in temperature that would occur due to the reaction, a heat bath is applied to the model, forcing the temperature to stay the same. By using the heat bath we can see the effect of running a reaction in an environment with different temperatures, and see how the envrionmental temperature affects reaction rate.
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<font size="4" face="Verdana, Arial, Helvetica, sans-serif">Some reactions
happen very quickly, like the explosion of TNT, and some happen very
slowly, like growing fingernails. However, the rates of these reactions
can be affected by two different factors: concentration of reactants and
temperature. </font>
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-47292aRaised Bevel140.01440.01440.01480.0true1414dropAtom2.gif14false685falseconcentration.cml32025false25false_blank14false1480.0true141480.0true1414play.gif141480.0true141480.0true1414reset.gif141480.01org.concord.modeler.ActivityButtonI'm not sure how to proceed. Give me a hint.35929Raised Bevel<html><font size="4"><ul><li>Click on the <strong><sup>+</sup>2</strong> button below and then click in the white container.</li><li>Each time you click you will drop an atom in that location.</li><li>Drop about 20 atoms in the container but spread them out evenly.</li><li>Then run the model.</li></ul></font></html>Hint80.01org.concord.modeler.PageSliderorg.concord.mw2d.models.ReactionModel4100.0100.02600.050Temperature902001falsetrueLineTemperatureorg.concord.mw2d.activity.ChemContainerrates$0.mmlfalseorg.concord.modeler.PageBarGraphMole Fraction A2(%)080200true510true-2b2f3840.0100.00.011org.concord.modeler.PageMultipleChoicetrue4550130<html>
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<font size="4" face="Times,serif"><strong>How does reactant concentration
affect the rate of a chemical reaction?</strong> In this example, the
formation of A<sub>2</sub>. </font>
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Concentration has no effect.Increased concentration increases the rate of reaction.Increased concentration decreases the rate of reaction.Increased concentration can either increase or decrease the rate of reaction.1 Line11org.concord.modeler.PageTextArea550<html>
<font size="4" face="Times,serif"><strong>Explain why concentration does or doesn't have an affect on reaction rate.</strong></font>
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<font size="4" face="Times,serif"><strong>How does temperature affect the
rate of a chemical reaction?</strong> In this example, the formation of A<sub>2</sub>.</font>
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Temperature has no effect.Increased temperature usually increases the rate of reaction.Increased temperature usually decreases the rate of reaction.Increased temperature can either increase or decrease the rate of reaction.1 Line11org.concord.modeler.PageTextArea550<html>
<font size="4" face="Times,serif"><strong>Explain why temperature does or doesn't have an affect on reaction rate.</strong> </font>
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